1. Field of the Invention
This invention relates to a roll changing apparatus of a rolling mill.
2. Description of the Related Art
The outline of a conventional roll changing device in a 4-roll type rolling mill will be described with reference to FIG. 11. FIG. 11 shows a concept of a conventional roll changing device called a 3-roll cluster type. As shown in this figure, a work roll assembly 3, composed of an upper work roll 1 and a lower work roll 2 equipped with chocks, is supported by upper and lower backup rolls 4 and 5. The upper and lower backup rolls 4 and 5, and the work roll assembly 3 are borne on a sled liner 6, and the sled liner 6 is supported by a pair of rails 7 in such a manner as to be admissible into and removable from a work side relative to a rolling mill 8. A floor surface of the rolling mill 8 is level with the position of the lower work roll 2. In an underfloor portion on the work side of the rolling mill 8, a space for moving the sled liner 6 and the lower backup roll 5 is formed in a ditch-like shape.
To change the upper work roll 1 and the lower work roll 2, the upper backup roll 4 is detached or lifted, while the lower backup roll 5 and the work roll assembly 3 are being borne together on the sled liner 6 in the rolling mill 8. Also, the sled liner 6 is pulled out onto the work side by driving means (not shown) for moving the sled liner 6 into and with respect to the rolling mill 8. At the pulled out position, the work roll assembly 3 on the lower backup roll 5 is detached and removed by a crane or the like. An alternative new or repaired work roll assembly 3 is placed on the lower backup roll 5, and the sled liner 6 is pulled into the rolling mill 8.
In the 3-roll cluster type roll changing device, the width of the under floor ditch on the work side (i.e., the width in the plate passing direction) is nearly equal to the width of the rolling mill 8. Thus, the work roll assembly 3 can be changed in a narrow space without the need to enlarge the space between the ditch and the rolling mill 8. Each time the upper work roll 1 and the lower work roll 2 are to be changed, however, the lower backup roll 5 needs to be pulled out of the rolling mill 8 by the sled liner 6. Furthermore, a crane or the like is used to change the work roll assembly 3, thus requiring a long time for the roll change.
Under these circumstances, a roll changing device of a so-called turn table type as shown in FIG. 12, or a roll changing device of a so-called side shift type as shown in FIG. 13 has been used. FIG. 12 shows the concept of the turn table type roll changing device, while FIG. 13 shows the concept of the side shift type roll changing device. The members identical to the rolling mill 8 shown in FIG. 11 are assigned the same reference numerals, and duplicate explanations are omitted.
As shown in FIG. 12, a moving frame 14 having a turn table 11, mounted thereto and being movable in the direction of an arrow A, is provided on the work side of a rolling mill 8. At positions on both sides of the center of rotation on the turn table 11, retracting rails 12, 13 for a work roll assembly 3 are provided in two parallel lines. The work roll assembly 3 can be carried from one of the retracting rails into the rolling mill 8, or from the rolling mill 8 into the one retracting rail.
Changing of an upper work roll 1 and a lower work roll 2 by the turn table type roll changing device is performed in the following manner: The worn-out, old work roll assembly 3 is pulled out of the rolling mill 8, and brought onto one of the retracting rails (rail 12) on the turn table 11 that has stopped coaxially with the work roll assembly 3. A new or repaired work roll assembly 3a is brought from the work side indicated by an arrow B onto the other retracting rail 13. In this state, the turn table 11 is horizontally turned 180 degrees to interchange the positions of the retracting rails 12 and 13. Then, the new or repaired work roll assembly 3a on the retracting rail 13 is drawn into the rolling mill 8. Whereas the old work roll assembly 3 on the retracting rail 12 is taken out to the work side indicated by the arrow B. A lower backup roll 5 is changed by moving the moving frame 14, which has the turn table 11 mounted thereto, in the direction of an arrow A to expose a retracting table (not shown) for changing of the lower backup roll 5 in a space between the rolling mill 8 and the moving frame 14, and replacing the old lower backup roll 5 with a new lower backup roll 5. With the turn table type roll changing device, the work rolls can be changed swiftly by operating the turn table 11.
As shown in FIG. 13, the side shift type roll changing device has a plurality of (two in the illustrated example) side shift tables 16 and 17 provided on a work side of a rolling mill 8 in such a manner as to be movable parallel to the passing direction of a plate. Changing of an upper work roll 1 and a lower work roll 2, according to the side shift type roll changing device, is performed in the following manner: One of the side shift tables, table 16, is stopped at a position facing a work roll assembly 3 of the rolling mill 8, and a worn-out, old work roll assembly 3 is retracted onto the side shift table 16. On the side shift table 17 adjacent to the side shift table 16, a new or repaired work roll assembly 3a has been placed. The side shift table 16 is freed from the position in front of the rolling mill 8, and then the side shift table 17 is moved to the position in front of the rolling mill 8 and stopped there. In this state, the new or repaired work roll assembly 3a on the side shaft table 17 is drawn into the rolling mill 8, while the old work roll assembly 3 on the side shift table 16 is taken out to the work side. Changing of a lower backup roll 5 is performed as follows: A ditch-like foundation is formed below a moving path for the side shift tables 16 and 17. A table (not shown) for changing the lower backup roll 5 is provided in the ditch-like foundation. The side shift tables 16, 17 are freed from the position facing the rolling mill 8, and the lower backup roll 5 is changed. With the side shift type roll changing device, like the turn table type roll changing device, the work rolls can be changed swiftly by a moving operation of the side shift tables 16, 17.
According to the turn table type roll changing device, the work rolls can be changed swiftly by operating the turn table 11. However, the turn table. 11 and the moving frame 14 are elaborate in configuration, and the foundation requires a special design, increasing the equipment cost. According to the side shift type roll changing device, the work rolls can be changed swiftly by a moving operation of the side shift tables 16, 17. However, there is need to consider a table shift space for retreat of the side shift tables 16, 17 during changing of the backup roll. This also requires an elaborately configured device, increasing the equipment cost.
In addition, the turn table type roll changing device and the side shift type roll changing device enable the work rolls to be changed more swiftly compared with the three-roll cluster type roll changing device. Thus, it is demanded to modify the existing three-roll cluster type roll changing device into the turn table type or the side shift type. However, this requires that the foundation be upsized markedly, or an elaborate device be mounted. Thus, the modification of the existing three-roll cluster type roll changing device requires huge manpower, labor hours, and costs, and has not been easy.
The present invention has been accomplished in light of the foregoing situations. An object of the present invention is to provide a roll changing apparatus of a rolling mill capable of swiftly changing work rolls without using elaborate devices. A particular object of the invention is to provide a roll changing apparatus of a rolling mill, which can be installed without requiring a marked modification of equipment in the existing three-roll cluster type roll changing device.
A first aspect of the invention is a roll changing apparatus of a rolling mill, comprising:
a pull-out rail, provided on a front surface of a work side of the rolling mill, for pulling out a work roll assembly;
a shift rail extending in a direction intersecting with the pull-out rail; and
shifting/driving means for moving the work roll assembly, which has been pulled out along the pull-out rail to an intersection of the pull-out rail and the shift rail, in a shifting direction along the shift rail.
According to this aspect, it is possible to move only the pulled-out work roll assembly easily in the shifting direction, without providing a turn table or shifting a table bearing a work roll assembly. As a result, a simple foundation structure permits replacement of the work roll assembly. That is, the old work roll assembly can be easily replaced by a new work roll assembly without the use of an elaborate foundation structure, so that the work rolls can be changed swiftly. Furthermore, there is no need for a wide installation area for the provision of a turn table or the shift of a table itself, and complicated foundation work is unnecessary. Thus, the roll changing apparatus of the present invention can be installed without the need for a marked modification of the existing rolling equipment, especially, the equipment of a three-roll cluster type roll changing device.
In the first aspect of the invention, the pull-out rail and the shift rail may be provided in such a manner as to intersect on a same plane, and at least the shift rail may be provided with a support member for movably supporting the work roll assembly. Thus, roll changing work can be done swiftly using a simple configuration.
In the first aspect of the invention, moreover, the pull-out rail and the shift rail may be provided in such a manner as to intersect on vertically different planes, and a site of the pull-out rail at an intersection in a plan direction of the pull-out rail and the shift rail may be composed of a moving bogie which supports the work roll assembly and which is moved along the shift rail by the shifting/driving means. Thus, the work roll assembly can be moved in the shifting direction by the movement of the moving bogie, so that roll changing work can be done swiftly using a simple configuration.
A second aspect of the present invention is a roll changing apparatus of a rolling mill, comprising:
a pull-out rail, provided on a front surface of a work side of the rolling mill, for pulling out a work roll assembly;
a shift rail movable in upward and downward directions, and extending in a direction intersecting with the pull-out rail;
hoisting/lowering driving means for lowering the shift rail at a time of pulling-out of the work roll assembly, and for hoisting the shift rail after the work roll assembly is pulled out along the pull-out rail as far as an intersection of the pull-out rail and the shift rail; and
shifting/driving means for moving the work roll assembly in a shifting direction along the shift rail when the work roll assembly has been pulled out to the intersection of the pull-out rail and the shift rails, and the shift rail has been hoisted.
According to this aspect, it becomes possible to move only the pulled-out work roll assembly easily in the shifting direction, without providing a turn table or shifting table bearing a work roll assembly. As a result, a simple foundation structure permits replacement of the work roll assembly. That is, the old work roll assembly can be easily replaced by a new work roll assembly without the use of an elaborate foundation structure, so that the work rolls can be changed swiftly.
In the first or second aspect of the present invention, the rolling mill may be provided with a lower backup roll for supporting a lower work roll, a ditch-like foundation for pulling out the lower backup roll may be provided on the front surface of the work side of the rolling mill nearly in correspondence with a width of the rolling mill, a table member may be detachably provided in the foundation, and the roll changing apparatus may be installed on the table member. Thus, by detaching the table member, the lower backup roll can also be replaced swiftly and easily.
The table member may be supported movably along a direction of pulling-out of the lower backup roll, and moving means for moving the table member may be provided. Thus, the table member can be detached quickly, and the lower backup roll can be replaced more easily. Besides, lower backup roll pulling-out/driving means for pulling out the lower backup roll may be provided, and the lower backup roll pulling-out/driving means may be applied as the moving means. Thus, the table member can be retreated in conjunction with the lower backup roll, and the lower backup roll can be replaced more easily.